Don’t Be Fooled by Moises Sierra’s 2013


Sept 3, 2013; Phoenix, AZ, USA; Toronto Blue Jays right fielder Moises Sierra (14) hits a double during the seventh inning against the Arizona Diamondbacks at Chase Field. Mandatory Credit: Matt Kartozian-USA TODAY Sports

The battle for the Blue Jays fourth outfield spot is well underway in Spring Training. Moises Sierra, Anthony Gose, and to a lesser degree, Kevin Pillar, are all in the running, but it’s Sierra who’s leading the pack early in camp.

Gose and Pillar have options remaining, which make them the smarter choices to start in AAA, while Sierra is out of options and would most likely be picked up if he were to be exposed on waivers.

Sierra and Gose, who are the favorites as of right now, bring very different tools to the fourth outfield spot. Sierra brings more power to the plate, is a more polished hitter, but is suited for a corner outfield role. Gose brings game breaking speed, and good defense to all three outfield spots.

Sierra offers a potential platoon option with Adam Lind, while Gose is a legitimate center field option behind Rasmus. While I believe they’ll both end up on the team eventually, I expect Sierra will be the one heading north with the Jays following the end of camp.

Working with Chad Mottola last year, it looked like Sierra sacrificed some home run power in order to use the entire field and put the ball in play more often. He put up a .290/.369/.458 line, far better than 2012 when he put up a .224/.274/.374. His line drive rate increased, his walk rate jumped to 11.5% and his strikeout rate dropped to 23.8%. Despite his HR/FB taking a dip to 4%, his SLG and ISO received large bumps because of his ability to find the gaps and drive the ball on a line more often.

The sample sizes from 2012 and 2013 are both very small, but similar in size, so using them in comparison is still a useful tool.

A lot of his 2013 numbers look great on the surface, and some fans seem convinced that he truly developed into a legitimate threat at the plate this season if he’s presented with significant AB’s, but to expect his slash line, walk rate and strikeout rate in 2014 to replicate 2013 is pure tomfoolery.

For his walk rate to jump from 3.9% in Buffalo to 11.5% in Toronto, a lot had to go right. Also, his BABIP of .385 is unsustainable. There’s no question that luck was on his side, even though there may have been a change in approach under Mottola.

Despite the bump Sierra received in his walk rate, and his improved strikeout rate, his plate discipline actually got worse in 2013. According to the Pitchf/x data at Fangraphs, he swung at nearly 4% more pitches outside of the strike zone bringing his O-Swing% up to 35.5%. He also increased his swing rate on pitches inside the strike zone by over 10%, not that it’s a bad thing to swing at more strikes, but it shows he became much more aggressive. An aggressive approach at the plate doesn’t usually correlate with a top 30 walk rate, especially when you swing at 35% of pitches outside of the strike zone.

Sierra did have a contact rate of 77% in 2013, which is a substantial increase over his 2012 rate of 69.8%. Once again, these numbers suggest he sacrificed power for contact. If he can keep developing a strong contact rate, but keep his HR/FB up, I believe he can be a contributor at the major league level, but that’s a difficult thing to achieve and he’ll need increased AB’s to get there.

His 2013 walk and strikeout rates won’t nearly be similar in 2014 if he continues his free swinging ways, and there’s no doubt that Sierra needs to improve his plate discipline if he wants to be a consistent performer over longer periods of time.

Alex Anthopoulos compared Sierra to Nelson Cruz back in 2012 when he was originally called up. The power and arm strength comparison is warranted, but Sierra will need to work on his plate discipline, and ability to hit for power without sacrificing too much contact in order to contribute like Nelson Cruz has.

Cruz has a career O-Swing% of 29.9%, including his career low in 2012 when he put up a 26.6% mark. His career contact rate is a steady 72.8%, but doesn’t sacrifice power based on his strong 16.6% career HR/FB, including three seasons over 21%.

Cruz’s career walk and strikeout rates of 7.9% and 22.3% should be regarded as a ceiling for Sierra. Clearly, Cruz has more experience then Sierra, and a much larger a sample size to analyze, but don’t let Sierra’s 2013 bloat your expectations.

Below are zone profiles from both Sierra and Cruz acquired from Brooks Baseball. They show swing rates for their 2013 seasons, and as you can see, Sierra has some work to do when it comes to pitch selection.

None of the squares outside of the strike zone of Cruz’ profile are over 50%, meanwhile Sierra has six squares over 50%. Obviously, Sierra’s is a much smaller sample size, but this gives you a visual example of the work Sierra has to do at the plate. On top of that, the brightest portions of Cruz’s profile are pitches that get the biggest parts of the plate, and the same can’t be said for Sierra. Not only does Cruz lay off more pitches outside of the zone, but he swings at better pitches that are inside the zone. Swinging at hitter’s pitches rather than pitcher’s pitches can go a long way in having success.

With the numbers and visual evidence presented, it’s easy to see why Sierra won’t reproduce a walk rate of 11.5%, and a slash line of .290/.369/.458. I’m not saying Sierra doesn’t have a future in the MLB. I firmly believe he can develop into a Nelson Cruz-type of player, but there’s no questioning he has plenty of improvements to make, and no one should expect him to make all of those this season and produce the same kind of numbers he had last year.